| LED Code | Meaning | Potential Issue | Solution |
|---|
| Light ON | No signal from thermostat | Thermostat not connected | Check thermostat wiring |
| Light OFF | Control failure | No power, bad wiring | Check breaker & wiring |
| 1 Flash | Ignition failure | Dirty flame sensor, faulty igniter | Clean flame sensor |
| 2 Flashes | Pressure switch stuck closed | Faulty switch, vent blockage | Replace switch |
| 3 Flashes | Pressure switch stuck open | Blocked hose, loose wiring | Check tubing |
| 4 Flashes | Open high limit | Clogged filter, wiring issue | Replace filter |
| 5 Flashes | Flame sensed with gas off | Faulty flame sensor, leaky gas valve | Replace sensor |
| 6 Flashes | Open rollout switch | Blocked heat exchanger, vent issue | Inspect heat exchanger |
| 7 Flashes | Low flame error | Low gas pressure, dirty sensor | Check gas pressure |
| 8 Flashes | Ignitor error | Faulty ignitor, bad wiring | Test and replace ignitor |
| 9 Flashes | Open pressure switch | Cracked hose, bad switch | Check tubing, test switch |
| Continuous Flashing | Reversed polarity | Incorrect wiring | Check electrical connections |